1. Field of the Invention
This invention relates to a biochemical analysis method and apparatus, wherein a sample, such as blood or urine, is spotted onto a dry chemical analysis element, such as a colorimetric-type dry chemical analysis element or an electrolyte-type dry chemical analysis element, by use of a spotting nozzle unit, and a substance concentration of a specific biochemical substance contained in the sample, an ionic activity of a specific ion contained in the sample, or the like, is determined.
2. Description of the Related Art
Colorimetric-type dry chemical analysis elements and electrolyte-type dry chemical analysis elements have heretofore been used in practice. When a droplet of a sample is merely spotted onto the colorimetric-type dry chemical analysis element, a specific chemical constituent or a specific physical constituent contained the sample is capable of being analyzed quantitatively. Also, when a droplet of a sample is merely spotted onto the electrolyte-type dry chemical analysis element, an ionic activity of a specific ion contained the sample is capable of being analyzed quantitatively. Biochemical analysis apparatuses utilizing the dry chemical analysis elements are capable of performing sample analyses easily and quickly and have therefore been utilized widely in medical facilities, medical laboratories, and the like.
Colorimetry utilizing colorimetric-type dry chemical analysis elements is performed in the manner described below. Specifically, after a sample has been spotted onto a dry chemical analysis element, the dry chemical analysis element having been spotted with the sample is kept at a constant temperature for a predetermined time within an incubator and is thereby caused to undergo a color reaction (i.e., a dye forming reaction). Thereafter, measuring light, which has wavelengths selected previously in accordance with a combination of a predetermined biochemical substance contained in the sample and a reagent contained in the dry chemical analysis element, is irradiated to the dry chemical analysis element, and an optical density of the dry chemical analysis element is thereby measured. The concentration of the predetermined biochemical substance contained in the sample is determined from the measured optical density and by use of a calibration curve having been formed previously, which represents a correspondence relationship between the optical density and the substance concentration of the predetermined biochemical substance.
Potentiometry utilizing electrolyte-type dry chemical analysis elements is performed in the manner described below. Specifically, in lieu of the optical density described above being measured, the ionic activity of a specific ion contained in a sample, which has been spotted onto an electrode pair comprising a pair of two dry type ion selective electrodes of an identical type, is determined through quantitative analysis with potentiometry by use of a reference liquid.
In each of the colorimetry and the potentiometry described above, the liquid-state sample is accommodated in a sample vessel (such as a blood-collecting tube), and the sample vessel accommodating the sample is set on a biochemical analysis apparatus. Also, the dry chemical analysis element necessary for the measurement is fed into the biochemical analysis apparatus. Further, by the utilization of a spotting nozzle unit comprising a spotting nozzle, which is capable of being moved in a predetermined direction, the sample is sucked up from the sample vessel and spotted onto the dry chemical analysis element having been conveyed to the position for spotting. Various techniques have heretofore been proposed for the loading of the sample, the dry chemical analysis element, a plurality of nozzle tips acting as expendables for the measurement, a mixing cup for dilution, a diluent liquid, a reference liquid, and the like, into the biochemical analysis apparatus.
From the view point of efficiency and operability, the biochemical analysis apparatus described above should preferably be constituted such that the biochemical analysis apparatus is capable of being loaded with a plurality of samples and is capable of performing the analyses successively. However, in such cases, the problems have heretofore occurred in that the size of the biochemical analysis apparatus cannot be kept small.